The present invention is directed, in general, to a method of forming a template and, more specifically, to a method of forming a dynamic template with a focused beam, and a system for use therein.
The semiconductor manufacturing industry is continually striving to manufacture smaller, faster and more reliable semiconductor devices. In its efforts to manufacture smaller, faster and more reliable semiconductor devices, the semiconductor manufacturing industry relies heavily on the ability to quickly and accurately add or remove a material from a precise microscopic pattern on a semiconductor device. For instance, it is common for material to be added or removed from microscopic patterns including circuit devices, such as trenches, interconnects, or photolithographic masks. This material is generally added or removed to correct a defect within the pattern.
Photolithographic masks are an important component in conventional semiconductor manufacturing processes. Thus, it is extremely important that the photolithographic masks be free of defects during patterning. Since the photolithographic mask is part of the beginning processing step used to define a device, any defect that is present in the photolithographic mask, typically is carried throughout the manufacturing process. Generally, defects in photolithographic masks may arise because of poor manufacturing, stray particles or use of the mask.
A set of photolithographic masks are typically quite expensive to manufacture and represent a major expense component to semiconductor manufacturers. The semiconductor manufacturing industry, in an attempt to reduce the escalating cost of replacing these photolithographic masks, developed a method of repairing such defects. Currently the semiconductor manufacturing industry uses a focused ion beam (FIB) tool to both add and remove material from precise microscopic patterns in the photolithographic masks.
To correct a defect in a photolithographic mask using the FIB process, the FIB tool manually follows a 2-dimensional template pattern that is transferred by a raster of a FIB beam. The raster of the FIB beam has a modulated dwell time at each pixel of the template; therefore, the amount of material removed or deposited depends on the dwell time at each pixel. The current process is generally capable of repairing most defects that may be detected in the microscopic pattern. However, it is severely limited by its manual characteristic, and as a result, has several drawbacks.
One of the drawbacks, is that it is only currently practical to use the FIB tool to repair a defect having a 2-dimensional projection, such as a uniform trench or hole, and not a defect having a 3-dimensional component. The problem is that simply stacking a series of fixed 2-dimensional templates propagates errors in the etching or deposition rate, accumulatively, and severely restricts any Z dimension complexity or variability of dimension or translation, during the FIB process. This introduces errors in the defect correction process.
Another drawback is that the current process is incapable of supporting even rudimentary automation. Thus, the current process requires an excessive amount of skill and time, and is non-repeatable. Moreover, unnecessary ion beam damage to the surface of the semiconductor device results from the current process. As the majority of the above discussion is focused on photolithographic masks, the FIB process may also be used to construct or correct defects in semiconductor features, such as trenches and interconnects. The same drawbacks occur when correcting defects in these semiconductor features, as occur.when correcting defects in photolithographic masks.
Accordingly, what is needed in the art is a process of accurately repairing defects on a precise microscopic pattern, that does not experience the.drawbacks experienced using the prior art process.
To address the above-discussed deficiencies of the prior art, the present invention provides a method of forming a dynamic template with a focused beam. The method includes forming a desired template that represents a desired image, forming an actual template that represents an actual image, such as a photolithographic mask or a semiconductor device feature, and comparing the desired template to the actual template to yield a deviation template. In one embodiment, the deviation template is formed by subtracting the actual template from the desired template.
Another embodiment taught by the present invention includes a dynamic template modification system for forming a semiconductor feature. The dynamic template modification system includes (1) a desired template that represents a desired semiconductor feature, (2) a scanning subsystem that generates an actual template that represents an actual semiconductor feature, (3) a template comparison subsystem, associated with the scanning subsystem, that analyzes the desired template and the actual template and generates a deviation template therefrom, and (4) a dynamic formation subsystem, associated with the scanning subsystem and the template comparison subsystem, that modifies the actual semiconductor feature using the deviation template and a focused beam subsystem, to substantially conform the actual semiconductor feature to the desired semiconductor feature.
The foregoing has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.